Comparison between the end-diastolic images and the summed images of gated 99mTc-sestamibi SPECT perfusion study in detection of coronary artery disease in women.

BACKGROUND: End-diastolic images (EDI) can be easily derived from technetium 99m-sestamibi gated single photon emission computed tomography (SPECT) perfusion study (SGS). This may reduce the effect of myocardial wall thickening during systole and potentially improve the sensitivity of radionuclide perfusion imaging, especially in patients with small hearts.

METHODS: This prospective study was conducted in 53 consecutive female patients to compare the diagnostic accuracy of EDI with that of the summed images (SI) of SGS. Fifty-three patients with suspected coronary artery disease (CAD), scheduled for coronary angiography within 2 months, were evaluated with SGS. Treadmill stress testing was used in 28 patients, and dipyridamole injection was used in the remaining 25 patients. A 2-day protocol was used as follows: stress test with 25 to 30 mCi of 99mTc-sestamibi and a rest study performed at least 24 hours later with the same dose. Sixteen frames per cardiac cycle were acquired for both the rest and the stress studies. Three end-diastolic frames were used for EDI, and all the 16 frames were summed for SI. SI and EDI data reconstruction were interpreted by 3 experienced blinded observers (consensus reading) during two distinct reading sessions, one with SI alone and the second with EDI alone. The heart was divided into 17 segments.

RESULTS: Coronary angiography showed > or = 50% stenoses in 1 or more major coronary arteries in 38 patients and was normal in 15 patients. The sensitivity was 73.7% (28/38) and 84.2% (32/38), respectively, for SI and EDI. Three of 4 patients with CAD not detected by SI but seen with EDI were considered to have relatively small hearts. The specificity was 86.7% (13/15) and 80.0% (12/15) for SI and EDI, respectively. On a total of 901 segments, 106 ischemic defects were detected by SI and 173 by EDI (P = .001). The segmental agreement between the two techniques was 88.6% (798/901 segments).

CONCLUSION: EDI showed more ischemic defects than SI, and there was also a nonsignificant trend toward an improved sensitivity of EDI in comparison to SI in detection of coronary artery disease in women, especially in patients with small hearts. EDI may be a useful adjunct to the standard perfusion imaging with SGS in such a clinical situation.